The $120,000 repair involves draining the 70,000-gallon tank and temporarily relocating fish while workers fix cracks in the rockwork, due to rusting rebar embedded within, which caused the rockwork to expand.

“This is by far our biggest tank,” Birch’s executive director, Nigella Hillgarth, said of the exhibit, which is located halfway through the aquarium and has public seating in front of it.

“It fills up the entire wall,” Hillgarth said. “It’s lovely; you can just sit and look at all the fish.”